1. Field of the Invention
The present invention relates to an element of a stepwise grid for waste incinerator furnaces endowed with improved air circulation and air-tightness characteristics, in particular for solid urban waste incineration.
2. Related Art
The incinerator furnaces for solid urban waste use stepwise grids on which the drying and the combustion of the waste occurs, also at high temperatures. The above-said steps must consequently allow such thermal expansion to allow the furnace to properly operate, and furthermore prevent that, during the alternative motion between stationary steps and moving steps, any waste being treated from accidentally penetrating between two adjacent steps.
For that purpose, the prior art provides side joint coverings, protruding from one side of the grid elements, and which can be coupled relative to the other smooth side of the adjacent grid elements, so as to secure the tightness against the infiltration of waste between adjacent steps.
It is furthermore known that such joint coverings should cooperate to accomplish the tightness necessary to prevent leaks of combustion air, so as to allow, together with the hollows provided in the grid, elements, a good blowing in of air.
So far, all of the above is at least partly accomplished, with an approximate tightness and a disordered air circulation, which are not always are able to guarantee perfect operation of the steps, the adequate cooling thereof, and an optimum tightness thereof to the waste.
The grid elements used to date are mounted by means of rear pivots, constrained through latch devices which do not allow them to be easily positioned or replaced.